Inspired by a thread on perforce-user the other day,
here is a trigger that enables variable expansion in
the protection table.
If we were to install this in the Public Depot and it
worked correctly, we could replace about 95% of our
(user-visible) protection table with the single line:
write user $user(registered) * //guest/$user/...
In my limited testing so far it seems to work pretty
nicely, but I wouldn't put it in production just yet.